The study was conducted to come across with competitive test pasture species grown in combination with parthenium at varying levels of density under field in factorial experiment using Randomized Complete Block Design. The treatments consisted of 10, 20 and 30 plants of either test species grown together with 30, 20 or 10 parthenium other than pure culture of each species with four replications. The species showed a significant degree of difference (P < 0.05) in inhibition efficiency on growth attributes of parthenium. Among the species, C. ciliaris, C. gayana and P. coloratum were strongly competitive (> 50% IE) while D. intortum and L. purpureus were ranked as moderately competitive (< 50% IE) with inhibition efficiency of 59, 68 and 73, 36 and 47% on dry matter biomass at heavier level of density respectively. At medium level of density the species had 39, 52 47, 21 and 25% and 11, 19 18, 9 and 13% IE at lower levels of density respectively. Increasing mixing level from the lower to medium density level their IE increased by 27, 33 and 29% while by 20, 16 and 26% when mixing level increased from medium to heavier level of density respectively. Similarly, at heavier density a reduction of 39, 44 and 52% on height, 30, 41 and 40% on number of tillers and/or branches and 24, 30 and 36% on leaf area of parthenium respectively. At this density, the species had RCC of 2.57, 1.69 and 2.33 and AI of 0.61, 0.52 and 0.68 respectively. Besides, a strong association seen concerning IE and growth attributes of species with a correlation coefficient of r = 0.848, 0.795, 0.549 and 0.413 between dry matter biomass, height, number of tiller and/or branch and leaf area respectively. Therefore, it can be suggested that successful management of parthenium can be achieved through biological approach using competitive pastures species in rangelands and/or other infested locations that believed to be cost effective, environmentally friendly and its sustainability could play a substantial role.

Shashie, A., 2007. The Impact of Parthenium (Parthenium hysterophorus L.) on the Range Ecosystem Dynamics of the Jijiga Rangeland, Ethiopia. The Msc thesis presented to the school of Graduate studies of Haramaya University, Ethiopia.